Dai Shuqin, whose sister was on board Malaysia Airlines Flight 370 that went missing on March 8, 2014, is stopped by policemen as she speaks to journalists near Yonghegong Lama Temple during a gathering of family members of the missing passengers, in Beijing Sunday, March 8, 2015. Families of the 239 people on board Malaysia Airlines Flight 370 on Sunday marked the anniversary of the plane's disappearance, vowing to never give up on the desperate search for wreckage and answers to the world's biggest aviation mystery. (AP Photo/Andy Wong)
(The Associated Press)

Dai Shuqin, right, and Jiang Hui, left, relatives of passengers on board the Malaysia Airlines Flight 370 that went missing on March 8, 2014, speak to journalists as they arrive near Yonghegong Lama Temple during a gathering of family members of the missing passengers, in Beijing Sunday, March 8, 2015. Families of the 239 people on board Malaysia Airlines Flight 370 on Sunday were marking the anniversary of the plane's disappearance with a vow to never give up on the desperate search for wreckage and answers to the world's biggest aviation mystery. (AP Photo/Andy Wong)
(The Associated Press)

Dai Shuqin, front right, and Jiang Hui, rear right, relatives of passengers on board the Malaysia Airlines Flight 370 that went missing on March 8, 2014, is intervened by policemen as they try to speak to journalists near Yonghegong Lama Temple during a gathering of family members of the missing passengers, in Beijing Sunday, March 8, 2015. Families of the 239 people on board Malaysia Airlines Flight 370 on Sunday were marking the anniversary of the plane's disappearance with a vow to never give up on the desperate search for wreckage and answers to the world's biggest aviation mystery. (AP Photo/Andy Wong)
(The Associated Press)

KUALA LUMPUR, Malaysia – The first comprehensive report into the mystery of Malaysia Airlines Flight 370 has revealed that the battery of an underwater locator beacon had expired more than a year before the plane vanished in March 2014.

Apart from that anomaly, the detailed report released Sunday devoted pages after pages to describe the complete normality of the flight, shedding little light on aviation's biggest mystery.

The significance of the expired battery was not immediately apparent, except indicating that searchers would have had lesser chance of locating the aircraft in the Indian Ocean, where it is believed to have crashed, even if they were in its vicinity.